Linear poly-n-haloaziridines



United States Patent 3,510,520 LINEAR POLY-N-HALOAZIRIDINES Allen F.Graefe, Claremont, Calif., assignor to Aerojet- General Corporation, ElMonte, Calif., a corporation of Ohio No Drawing. Continuation-impart ofapplication Ser. No. 282,136, May 21, 1963. This application Jan. 20,1967, Ser. No. 610,504

Int. Cl. A01n 9/20; C07c 87/20; C08f /00 U.S. Cl. 260583 1 ClaimABSTRACT OF THE DISCLOSURE A germicidal polymer having the formula:

CH2CHzNX where X is a halogen and n is a whole number greater than oneuseful as general sanitizing agents, germicides and fungicides.

The instant application is a continuation-in-part of copendingapplication Ser. No. 282,136, filed May 21, 1963, now abandoned.

"SUMMARY OF THE INVENTION wherein X is a halogen having an atomic weightup to about 127, i.e., fluorine, chlorine, bromine and iodine, and n isa whole number greater than one and represents the number of repeatingunits in the polymer chain. It will be appreciated that in any givenbatch of product, molecules may vary in length from several to tens ofthousands of repeating units. Hence, molecular weight figures representstatistical averages. The exact nature of terminal groupings is notknown and will vary depend ng upon whether polymerization agents,chain-stopping agents, etc. are present. Preferably, the averagemolecular weight of the polymer products is in the range from about20,000 to about 50,000.

The novel linear polymers of my invention may be prepared by twomethods.

Method No. 1: Polymerization of N-haloaziridines. Poly-N-haloaziridinesmay be prepared by polymerizing the corresponding N-haloaziridine havingthe formula:

wherein X has the meaning shown above, in the presence of a strong acidcatalyst. Preferably an acid at least as strong as phosphoric is used.Suitable acids include sulfuric, phosphoric, nitric, maleic, oxalic andphosphorous. A catalytically effective amount of acid is employed, butpreferably about one part of acid for five parts of halo- "ice aziridineis used. Acid in excess of this amount may be employed; however, whenexcess acid is used, the resulting product is contaminated somewhat withacid so that it must be purified. When about one part of acid is used 5for five parts of haloaziridine, no acid is obtained in the finalproduct.

The temperature at which the polymerization can be conducted rangesgenerally from about 80 C. to about 72 C. At temperatures above 72 C.,the polymer product decomposes to form unwanted products. The pressureunder which the reaction takes place is not critical and preferablyatmospheric pressures are employed. However, higher pressures up toabout 50 atmospheres may be employed, if desired.

The solid poly-N-haloaziridine product is essentially linear and may berecovered by any of the common liquidsolid separation means such asfiltration, decantation or centrifugation. The solid product may then bewashed with a slightly acid aqueous solution to purify the product from0 any excess acid. Aqueous sulfamic acid is a preferred washing agentsince sulfamic acid is a non-volatile solid and will provide a slightlyacid residue upon drying, which will prevent attack by bases causingproduct decomposition.

The following examples are given in illustration and are not intended tolimit the scope of the invention. Parts and percentages are by weightunless otherwise indicated.

EXAMPLE I To 0.844 g. (10.89 mmoles)) of N-chloroaziridine at 0 C. wasadded 0.111 g. of 85% phosphoric acid (0.094 g. or 0.96 mmole of purephosphoric acid). A white precipitate appeared within a few seconds.Stirring was continued during a fifteen minute warming period andsubsequently for two hours at ambient temperature. The suspension wasthen poured into 5 ml. of 0.01 Normal aqueous sulfamic acid (H NSO H)and the solution was filtered through a medium frit. The white solid waswashed with 5 ml. of 0.01 Normal aqueous sulfamic acid in two portionsand was subsequently dried to constant weight under vacuum at ambienttemperature. A total of 0.352 g. of white solid was recovered, or 4.54milliformulaweights calculated as poly-N-chloroaziridine. Aformulaweight is the weight in grams of one unit of the polymer chain.Polymerization had therefore proceeded to the extent of 41.7% and onepart of acid was effective in polymerizing 4.7 parts ofN-chloroaziridine. A sample of the dry solid was analyzed for positivehalogen. The results indicated a purity of 92.9% calculated aspoly-N-chloroaziridine.

It is also within the scope of this process to polymerize theN-haloaziridine in the presence of a strong acid and also a halogenatingagent such as those described below in Method 2. The halogenating agentserves as a cocatalyst to obtain higher yields and/or higher purity.

EXAMPLE II To 0.409 g. (5.28 mmoles) of N-chloroaziridine at 0 C. wasadded 0.061 g. (0.56 mmole) of t-butyl hypochlorite. The liquids weremiscible and there was no 60 evidence that a reaction had occurred. Tothis stirred solution, was added 0.050 g. of 85% phosphoric acid (0.043g. or 0.44 mmole of pure phosphoric acid). This resulted in a violentreaction accompanied by the immediate formation of a heavy whiteprecipitate. The reaction mixture was stirred for fifteen minutes at 0C. and subsequently for twenty-five minutes at ambient temperature. Thevolatiles were removed under reduced pressure at ambient temperatureleaving 0.201 g. of white solid or 2.60 milliformulaweights of poly Nchloroaziridine. Polymerization had therefore proceeded to the extent of39.2%. The solid was taken up in 0.01 Normal aqueous sulfamic acid,washed, dried and analyzed as described above. The results indicated apurity of 90.5 percent calculated as poly-N-chloroaziridine.

When N-chloroaziridine is replaced by N bromoaziridine orN-iodoaziridine, poly-N-bromoaziridine and poly-N-iodoaziridinerespectively are obtained.

Method No. 2: Poly-N-haloaziridines may be prepared by the halogenationof polyethylenimine.

Halogenating agents which are suitable in this method include anyhalogenating agents which do not form a strong base upon reaction. Anagent such as NaOCl forms NaOH upon reaction and would not be suitable.Suitable halogenating agents include chlorine, bromine, iodine, fluorineand agents containing an OCl, O-Br, OI or OF bond such as tertiary butylhypochlorite.

Reaction takes place according to the following scheme; using t-butylhypochlorite as an example:

Sufficient halogenating agent must be employed so that one halogen atomis present for each repeating unit in the polyethylenimine chain.Generally, it is desirable to employ a slight excess of the halogenatingagent.

The reaction takes place in the presence or absence of a solvent.Solvents which may be employed include slightly acid aqueous solutions.An excess of liquid halogenating agent may also act as the solvent. Thetemperature and pressure under which the reaction can be conducted arethe same as that discussed above for Method No. 1.

The solid product obtained by this method may be recovered by any of thecommon liquid-solid separation means such as decantation, centrifugationand filtration. The product may then be washed with a slightly acidaqueous solution to remove any acid present in the product.

EXAMPLE III To 215 g. of 50 percent aqueous polyethylenimine (25 mmolesof polyethylenimine) was added ml. of water and ml. of glacial aceticacid. To the resulting clear solution at 5 C. was added with stirring2.9 g. of t-butyl hypochlorite (25 mmoles) over a period of ten minutes.A white precipitate formed during the addition. After continued stirringfor 15 minutes following the addition of t-butyl hypochlorite, themixture was slowly warmed to ambient temperature. The solution wasfiltered with suction and the solid was dried under vacuum at ambienttemperature to constant Weight (0.40 g. or percent of theory). Ananalysis of the solid for positive chlorine indicated a purity of 95.6percent calculated as poly-N-chloroaziridine.

EXAMPLE IV A suspension of polyethylenimine in aqueous-methanolicsulfuric acid was prepared from 2.15 g. of 50 percent aqueouspolyethylenimine mmoles of polyethylenimine) ml. of water and 15 ml. of4 Normal sulfuric acid in methanol. To the Well-stirred suspension at 5C. was added 2.9 g. of t-butyl hypochlorite (25 mmoles) during a tenminute period. Initially, the yellow color of the t-butyl hypochloritepersisted and it appeared that no appreciable increase in the amount ofundissolved solid occurred. However, nearing the completion of theaddition of t-butyl hypochlorite, a voluminous-white precipitateappeared with the simultaneous decolorization of the solution. Themixture was stirred for an additional 15 minutes at 5 to 8 C. and wassubsequently warmed slowly to ambient temperature. The solution wasfiltered and the solid washed three times with 0.01 Normal sulfuricacid. The vacuum-dried solid weighed 0.92 g. (46 percent yield)calculated as poly-N-chloroaziridine). A sample of this material whendissolved in 1 Normal sulfamic acid and an aliquot an alyzed forpositive halogen was found to contain 100.2 percent of that expected forpoly-N-chloroaziridine. The titration of additional aliquots over athree day period indicated no change in positive halogen content. Thefinal aliquot was heated to reflux above 100 C. for one and one-halfhours. No precipitation or colorization of the solution occurred duringthis period. Analysis of the cooled solution indicated a loss inpositive halogen of 6 percent which indicated that very littledecomposition had occurred.

When free chlorine is used as the chlorinating agent instead of t-butylhypochlorite, in Example 1V above, a good yield ofpoly-N-chloroaziridine is obtained.

When free bromine and free iodine are used as halogenating agents, thecorresponding poly-N-haloaziridines are obtained.

Each step of the above processes is preferably carried out withagitation. While agitation is not critical, it is preferred since a moreeven reaction rate is obtained.

The time required for each of the above-disclosed processes is notcritical and depends upon other reaction conditions. Generally, however,a time period of ten minutes to twenty-four hours is sufficient.

I claim:

1. As compositions of matter essentially linear polymers having theformula:

L I.. wherein X is a halogen selected from the group consisting ofchlorine, bromine and iodine, and n is a whole number selected such thatsaid polymers have an average molecular weight of from about 20,000 toabout 50,000.

References Cited UNITED STATES PATENTS 2,271,378 l/1942 Searle.

CHARLES B. PARKER, Primary Examiner R. L. RAYMOND, Assistant ExaminerU.S. Cl. X.R.

